1. Field of the Invention
This invention relates to apparatus for transporting flowable particulate material and is an improvement in the invention described and claimed in U.K. Pat. No. 1,362,509 which itself is an improvement in the invention described and claimed in U.K. Pat. No. 1,332,837.
2. Description of the Prior Art
The teachings of U.K. Pat. No. 1,332,837 and U.K. Pat. No. 1,362,509 are hereby incorporated by reference in the instant application.
The claims of U.K. Pat. No. 1,362,509 provide apparatus of the kind comprising a container for receiving the material to be transported, said container including a material receiving chamber and a gas inlet chamber adjacent said material receiving chamber and separated therefrom by a porous wall, a material inlet in said container communicating with said material receiving chamber, means for opening and shutting said material inlet, a gas inlet connected to said gas inlet chamber, means for opening and shutting said gas inlet, a material outlet permitting transportation of material from said material receiving chamber, means for opening and shutting the material outlet, a pressure sensor in said material receiving chamber, and means operated by said pressure sensor when sensing a predetermined pressure in said material receiving chamber for opening said material outlet, wherein said material outlet comprises a conduit between said material receiving chamber and a location external to said container, one end portion of said conduit being permitted relative longitudinal movement with respect to another portion of said conduit to provide a predetermined spaced relationship between said one portion and said porous wall.
In an embodiment of the invention described in said U.S. Pat. No. 1,362,509, the apparatus for transporting flowable particulate material comprises an upstanding cylindrical container, the lower part including a tapered portion from which a right cylindrical portion depends. The lower end of the right cylindrical portion has a radial flange to which an end cap is secured, the end cap defining a gas inlet chamber separated into two parts by a gas inlet compartment. The gas inlet chamber is separated from the remainder of the container, constituting a material receiving chamber by a porous wall of ceramic material having apertures therein.
The upper surface of the porous wall mounts an abutment plate adjacent the lower end of an upstanding cylindrical conduit constituting a material outlet. The upper part of the conduit passes outwardly of the container through the top thereof and the lower part is curved to be in coaxial alignment with the container. The lower part of the upper portion of the conduit is attached to the radially inner wall of a coaxial and cylindrical connecting sleeve which depends from the upper portion of the conduit. The lower part of the radially inner wall of the sleeve is threaded to provide a coaxial connection with a second portion of the conduit depending therefrom. The second portion comprises an upper part which tapers towards the top of the container. The lower part has a greater diameter than the upper part. The arrangement is such that rotation of the second portion of the conduit within the sleeve causes axial movement of the second portion towards or away from the first portion according to the sense of rotation. Such axial movement varies the spacing between the lower end of the second portion and the upper surface of the porous wall, the spacing being predetermined according to the material being handled and defining an annular inlet in cooperation with a conical member.
The conical member defines a nozzle comprising a cup-shaped element whose base is uppermost in juxtaposition with the base of a frusto-conical stainless steel element which is coaxial thereto and tapers upwardly. The mouth of the cup-shaped element is dimensioned to sealingly engage an annular rim formed on the abutment plate. The two elements are retained in position by a stainless steel bolt passing downwards and coaxially through the two elements. The upper part of the bolt includes a conical head which tapers upwardly, the lower end of the bolt being screwed into a frame connected to the abutment plate. The cup-shaped element has a porous side wall formed of sinter bronze. The porosity of the side wall is sufficient to allow a gas, such as air, to permeate therethrough but insufficient to allow any material being handled to pass therethrough. The cup of the cup-shaped element communicates with a gas inlet compartment by means of a conduit extending therebetween. A conical member extends coaxially and upwardly into the second portion of the material outlet conduit. Thus, the size of the annular inlet may be varied by axial movement of the second portion of the material outlet conduit with respect to the remainder of the conduit and the conical member.